Part of major data model top level revamp, containing respective content roots in an encompassing combo root.
Part of major data model top level revamp, containing respective content
roots in an encompassing combo root.

RootContentNode.visit(): If we lack any storage_root_url then we can't even
try to visit. Otherwise, do the storage visit, configured to notify of
success, when we can then also do the personal storage visit.

RootContentNode.notify_subvisit_status(): Handle root node completion
reports appropriately, placing copies of formatted data in our page and
chaining to subsequent nodes, when successful, or indicating authentication
needed when not.

RootContentNode.authenticated(): Activate or deactivate presentation of
RootContentNode with login challenge versus content, depending on success
of access to sub roots.

SpiderOak/so_client_html5,SpiderOak/so_client_html5